Phantom602 wrote:I know they are custom built ones with very low impedance. The low impedance is the key. Without this the transformer could not diliver the current when needed. You did get the transformers right?

The reason I ask is... I got all the parts for 4 amps... minus 2 transformers ( I have 6 )... I have Sunfire working on the other pair. I hope Rita will be able to pull some magic out of her hat of tricks.

Roland says he is prett sure the Sunfire Signature 300x2 tansformers will work just as well. Problem is... that's a China part, and I don't know if Sunfire can scrape up a set for me.

It'll cost more than a dime, but you can have a specialty x-nfrmr shop custom build you two if you have one you could give them. Keep in mind, they MAY have to destroy the one you give them to do so. [estimated 600-750 per x-nsfrmr]

In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence.

The best way to enjoy digital music reproduction is to never listen to a good analogue reproduction.

treitz3 wrote:It'll cost more than a dime, but you can have a specialty x-nfrmr shop custom build you two if you have one you could give them. Keep in mind, they MAY have to destroy the one you give them to do so. [estimated 600-750 per x-nsfrmr]

Do you think having the actual transformer will be enough to get a few made ?? I do not have anything on them as far as specs go.
I need (2)... if they rip one apart to make the new ones, I will need (3).
Might just be a good idea to go ahead and make a few extra huh.. say 8-10 ?

A good transformer company can measure the electrical and resistance to get the design needed. It is unlikely the transformere will need to be damaged. If it comes to that then I would go ahead and get a few extra built.

Those are EI core transformers. Nothing really special about them. Do not try toroid types. The inrush current will be silly and the originals use the top plate as a heat sink (along with the outputs). The down converters use the sides as a heat sink and are thermally decoupled from the top.

If anyone knows where Vic Richardson is, talk to him. He is the engineer who finished this design and put it out the door. I'd love to say hi to him again.

So, the transformer. It should be around 180 VAC center tapped. You can measure the core size to get an idea of what the wattage is. Oversizing it slightly will not hurt as long as the two still fit.

Where ever did you get those PCB's from????

If you see any with heat sink grease under the output transistors, I probably rebuilt them. IF you don't, they should be taken apart and cleaned. We did have trouble with debris under the transistors that would sometimes short. This can take a while to happen. Get it before it gets you! Also, the feedback resistor needs to have the wattage at least doubled and stood up off the PCB.